Date of Award

8-26-2022

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Communication Sciences and Disorders

Advisor(s)

Soren Lowell

Keywords

Effortful Swallow, Hyolaryngeal Movement, Swallowing, Tongue Pressure

Subject Categories

Communication Sciences and Disorders | Medicine and Health Sciences | Speech Pathology and Audiology

Abstract

Purpose: The purpose of this study was to investigate the effects of the effortful swallow maneuver under two different instructions on tongue-to-palate pressure and hyolaryngeal displacement in healthy adults. Studying typical kinematic parameters and pressure generation in healthy individuals is critical for differentiating normal from pathological patterns and for determining swallowing parameters that can be targeted to optimize and individualize treatment plans for people with swallowing disorders. The primary objectives in this study were: (1) to determine the physiological effects of two different types of effortful swallows on anterior and posterior tongue pressure generation, hyoid displacement, and hyoid-larynx approximation in healthy adults, (2) to determine age-related differences in tongue-to-palate pressure and hyolaryngeal displacement in healthy adults, and (3) to determine the association between perceived effort used to swallow and tongue pressure within swallowing conditions.Method: Forty healthy adults (20 younger, 20 older) participated in this study. All participants were in general good health, were screened for normal oral structures, function, and swallowing skills, had normal tongue strength, were eating a normal diet, and had normal auditory comprehension skills. Experimental procedures included simultaneous data acquisition of tongue pressure, submental muscle activity, and hyolaryngeal movement during normal saliva swallows and effortful saliva swallows under two different instructions (tongue emphasis and neck squeezing). Measures of tongue pressure were obtained using the Iowa Oral Performance Instrument. Submental muscle activity during swallows was assessed using surface electromyography. Hyoid excursion and hyoid-larynx approximation were obtained during ultrasonography. All outcome measures were scaled to account for differences between participants and they reflected activity during swallowing. Moreover, participants rated their perceived effort used to swallow with a visual analog scale. Results: Significant tongue pressure differences were observed between swallowing condition and tongue region. The effortful swallows performed with tongue emphasis (EFSst) and pharyngeal squeezing (EFSsp) produced greater tongue-to-plate pressures than normal swallows (NSs). Additionally, posterior tongue pressures were greater than pressures generated in the anterior tongue region during NSs and EFSst. Hyolaryngeal measures were also greater during EFSst and EFSsp than NSs. Significant differences were found between the two types of effortful swallows in tongue pressure and hyoid displacement measurements. Overall, EFSst produced greater changes in these physiological measures than EFSsp. Significant age-related differences were only found in hyoid-larynx approximation during the EFSst. Moderate correlations were identified between tongue pressure and hyoid displacement during NSs and EFSst and between tongue pressure and hyoid-larynx approximation during NSs and EFSst. Results also showed that participants perceived greater effort used to swallow during EFSst and EFSsp than NSs. Finally, there was a significant, moderate correlation between perceived swallowing effort and objectively measured tongue-to-palate pressure during NSs and EFSst. Conclusions: The effortful swallow maneuver increases tongue-to-palate pressure and hyolaryngeal excursion in healthy adults across the age span. Additionally, different instructions for the effortful swallow affect those physiological measures. These findings have the potential to guide treatment decisions when recommending and training the effortful swallow maneuver. It may be helpful for clinicians to individualize and determine the optimal effortful swallow instructions for each patient based on their physiological swallowing impairments.

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